This mute has enabled hours of practice for my apartment living situation. There is relatively little information about it online and the price is certainly quite steep, but for me it is totally worth it.
It mutes the saxophone about 25 dBs, which is quite a lot, and leaves the output sound at around 75-80 dBs if you are blowing really hard on the horn. This is essentially the volume of a loud tv, so very much in the range of what is accepted inside an apartment building.
The downside is that anything below D will be a bit difficult to get to sound, and this can be a bit frustrating for beginners. I do not find it has a higher resistance as other reviews online suggest, but that might be my own experience.
The sound is a bit buzzy if you play without headphones, but plugging the headphones to the microphone eliminates the buzz and makes the sax sound great to be honest (I use the ones that are included with the mute).
The first few times it takes a while until you make the right adjustments in the stoppers inside the mute, but once you find the sweet spot you are good to go. I am using a YTS-25 and it fits pretty well.
If you have an issue with noise during your practice and can afford this mute, I would totally recommend that you buy this product.